Tableau Allows custom color palettes so you can add the official UM Colors to use in your vizzes. 

You can add as many custom palettes as you like to your Preferences.tps file, each with as many colors as you want. When you modify Preferences.tps to add colors, use the standard HTML format for the new colors (hexadecimal value #RRGGBB or Red Green Blue format). When you save the workbook and restart Tableau Desktop, the color palette names you added to Preferences.tps appear in the Select Color Palette drop-down list (Edit Color dialog). You can use a new palette like you would any other.

Tableau doesn't test or support custom color palettes, so be sure to back up your workbooks before you continue. Also, there is no guarantee that custom color palettes you create will work with future Tableau Desktop upgrades. 

The Preferences.tps file is located in your My Tableau Repository. The file is a basic XML file that you can open in a text editor to modify. An unedited preferences file looks like this:

To edit your preferences file:

1. Go to the My Tableau Repository folder in your Documents directory, and open the Preferences.tps file. 
2. Between the opening and closing workbook tags, insert opening and closing preferences tags.
   
3. Insert Custom Color palette XML (see below for examples)
4. Save the Preferences.tps file and then restart Tableau Desktop.

   When you open the Edit Colors dialog box and choose Select Color Palette, the color palette you added will be at the bottom of the palette list.

<?xml version='1.0'?>

<workbook>
   <preferences>

<!-- University of Michigan Color Schemes -->
         <!-- Colors Sourced from UM Global Communications Brand Standards Color Style Guide -->
         <!-- Accessed March 18th 2014 -->
         <!-- http://vpcomm.umich.edu/brand/style-guide/design-principles/colors -->
         <!-- Credit to Jamie Estil -->
         <!-- http://igulo.blogspot.com/2014/03/custom-color-palettes-in-tableau.html -->
         <!-- https://github.com/jestill/tableaux/blob/master/config/Preferences.tps -->

         <!-- Diverging Maize to Blue -->
         <color-palette name="UM Maize to Blue" type="ordered-diverging" >
            <color>#ffcb05</color>
            <color>#00274c</color>
         </color-palette>
         <!-- Categorical Maize and Blue -->
         <color-palette name="UM Cat Maize and Blue" type="regular" >
            <color>#ffcb05</color>
            <color>#00274c</color>
         </color-palette>
         <!-- UM Web Color Pallete -->
         <color-palette name="UM Web" type="regular" >
            <color>#ffcb05</color> <!-- maize -->
            <color>#00274c</color> <!-- blue  -->
            <color>#cfc096</color> <!-- umma tan -->
            <color>#9b9a6d</color> <!-- burton tower beige -->
            <color>#989c97</color> <!-- the rock gray -->
            <color>#e4e1df</color> <!-- observatory white -->
            <color>#a79d96</color> <!-- angell hall ash -->
            <color>#655a52</color> <!-- law quad stone -->
            <color>#7a121c</color> <!-- hill brown -->
            <color>#cc6600</color> <!-- lsa orange -->
            <color>#7e732f</color> <!-- archway ivy -->
            <color>#83b2a8</color> <!-- rackham roof green -->
            <color>#587abc</color> <!-- canham pool blue -->
            <color>#587abc</color> <!-- matthaei violet -->
         </color-palette>
         <!-- UM Print Media Neutral Colors -->
         <color-palette name="UM Print Neutral" type="regular" >
            <color>#ffcb05</color> <!-- maize -->
            <color>#00274c</color> <!-- blue  -->
            <color>#CFC096</color> <!-- umma tan -->
            <color>#9B9A6D</color> <!-- burton tower beige -->
            <color>#989C97</color> <!-- the rock gray -->
            <color>#A79D96</color> <!-- angell hall ash -->
            <color>#655A52</color> <!-- law quad stone -->
            <color>#111B22</color> <!-- puma black -->
            <color>#7A121C</color> <!-- hill brown -->
            <color>#CC6600</color> <!-- lsa orange -->
            <color>#7E732F</color> <!-- archway ivy -->
            <color>#83B2A8</color> <!-- rackham roof green -->
            <color>#587ABC</color> <!-- canham pool green -->
            <color>#575294</color> <!-- matthaei violet -->
         </color-palette>
         <!-- UM Print Media Bright Colors -->
         <color-palette name="UM Print Bright" type="regular" >
            <color>#ffcb05</color> <!-- maize -->
            <color>#00274c</color> <!-- blue  -->
            <color>#B32017</color> <!-- tappan red -->
            <color>#EA7F1E</color> <!-- ross school orange -->
            <color>#B9B309</color> <!-- wave field green  -->
            <color>#00B1B0</color> <!-- taubman teal -->
            <color>#0F6CB6</color> <!-- arboretum blue -->
            <color>#6F2A8E</color> <!-- ann arbor amethyst -->
         </color-palette>
         <!-- All UM Print Media Colors -->
         <color-palette name="UM Print All" type="regular" >
            <color>#ffcb05</color> <!-- maize -->
            <color>#00274c</color> <!-- blue  -->
            <color>#CFC096</color> <!-- umma tan -->
            <color>#9B9A6D</color> <!-- burton tower beige -->
            <color>#989C97</color> <!-- the rock gray -->
            <color>#A79D96</color> <!-- angell hall ash -->
            <color>#655A52</color> <!-- law quad stone -->
            <color>#111B22</color> <!-- puma black -->
            <color>#7A121C</color> <!-- hill brown -->
            <color>#CC6600</color> <!-- lsa orange -->
            <color>#7E732F</color> <!-- archway ivy -->
            <color>#83B2A8</color> <!-- rackham roof green -->
            <color>#587ABC</color> <!-- canham pool green -->
            <color>#575294</color> <!-- matthaei violet -->
            <color>#B32017</color> <!-- tappan red -->
            <color>#EA7F1E</color> <!-- ross school orange -->
            <color>#B9B309</color> <!-- wave field green  -->
            <color>#00B1B0</color> <!-- taubman teal -->
            <color>#0F6CB6</color> <!-- arboretum blue -->
            <color>#6F2A8E</color> <!-- ann arbor amethyst -->
            <color>#B5985A</color> <!-- diag m metallic -->
         </color-palette>
         <color-palette name="UM Expanded" type="regular" >
            <color>#ffcb05</color> <!-- maize -->
            <color>#00274c</color> <!-- blue  -->
            <color>#e5e5e5</color>
            <color>#40658f</color>
            <color>#0d57aa</color>
            <color>#002a5b</color>
            <color>#024794</color>
            <color>#886b01</color>
            <color>#333333</color>
            <color>#555555</color>
            <color>#465d85</color>
            <color>#eff0f1</color>
         </color-palette>

   </preferences>
</workbook>