Since this is technical writing, the concise nature of tables is appropriate and may make the information easier to scan quickly. You could try something like:

    Vary your shirt color to achieve different goals according to the table below:
    
        Goal             |  Shirt color
        ==============================
        Appear offensive | Red
        Look fresh       | White
        Express doubt    | Green
        Hide dirt        | Black

The table structure helps to enforce parallel structure.  It reduces redundancy in the use of "one," but also removes redundancy in the introductory, "If you want to..."