The lines of your coloring page are the rules you need to share with your team, share with them the boundaries. They are more likely to stay with in the lines if they know that they exist. Next by holding the work up for group and team acceptance they become their own self policing force. They can set self expectations and make constructive self criticism as well. The reward is acceptance and recognition from the team, an old saying is that a person can starve without any feedback, but only needs one good compliment to be filled to overflowing.
Coloring in is one of the main starting points of creativity in children. Being able to expressed ones self with a piece of paper and colored pencils or crayons is a great thing to be able to do and remember, it leads onto being able to learn other brand new skills. Quick tip! If your child has difficulty holding a colored pencil then try them with crayons first. Crayons are easier to hold because they are larger and softer. But as your childs skills and abilities progress they will prefer the greater accuracy of using colored pencils.