Have a look at the WikiFormatting guide (you should have a copy of it in your Trac project):

http://trac.xp-dev.com/publictrac/wiki/WikiFormatting

In a nutshell, you would use one of the many wiki processors supported by Trac.

Adding colors is as simple as:

{{{
#!html
<h1 style="color: orange">This is raw HTML</h1>
}}}

That example page uses the processors themselves, so, all of them should work.