Well, you have 7 activities listed at the bottom of the screen (I think, I'm no linguist, don't even know if it is Spanish or Portugese ....).
If you create a simple MySQL table consisting of 3 columns, activity_id, activity_name and activity_color you can always pull the correct color from the db, and if you want to change the color of a particular activity, all you need is one simple change to the db.
HTH - Blu