I am not sure if what I have is exactly what you are looking for, yet I added a downloadable version of the styles.php (I will add a copy here) in a previous post, that shows exactly where to edit changing the colors of header cells etc. by using a gradient.jpg. I aso posted various color gradients for everyone's use. It may not be a "map", but from this it is fairly easy to see where the different cells can be changed simply by editing the "gradient1.jpg" to any other.
To see my version in operation go to http://lwbi.net/moodle1/