When adding color to visualizations, keep an eye on how you use it. Any design creates its own local system of rules. If the system is coherent and consistent, there will be no difficulty in understanding it. Once you have defined a rule, including the color rule, stick to it until the end.
If in one diagram a category is given a dark blue color, then when this same category is repeated in other diagrams, make sure that it is also dark blue there. Otherwise, you create a risk of breaking the rule system and making things hard to understand.
