I do not like my entities to be light blue, what can I do?
Change the format for entities!

Go to Design Properties (either double-click the Design name in Browser or right-click and select Properties). Go to Format:

Double-click the Entity row (or press the XYZ icon) and select background color and border color preferred for entities.

If you select the Font tab you can define the fonts for elements related to entities, such as attributes, datatypes or primary key elements.

If you select the Default Line Widths and Colors tab you can define the line colors and widths to elements displayed as lines in Data Modeler diagrams.

You can define these Format properties to several element in Data Modeler, not just entities.