Hi luckyaba,
Go to your Admincp ---> Usergroup Manager ---> The group you want to have colored username ---> In the Username HTML Markup, there are two inputs. In the first input, type in
Code:
<span style="color: red>
where red is, you can put any color you want. If its a nonstandard color you will have to put the hex # of the color. And in the second input, you just type
And save.
Ryan