Hi,
what is "another color"?
And what did you try?
I see that you use the "fruity" theme.
There is the first option to change the variation in the "theme options". Here you can select of all color themes that are available for the backend, too.
Next: selecting "Inherit everything" = "No" you will find a lot more options - colors, symbols, fonts, etc.
Well, that's the very easy way.
The next step is to customize your template in the theme editor.
Joffm