For each calendar (except basic), you can preset the coloring of issues according to different criteria, for example, such as:
Highest priority tasks
Alex's Tasks and Peter's Tasks
Issues from Boss
Front-end tasks
Etc.
All users with access to the calendar will be able to see the conditional colors.
How to create calendar conditional colors
Create a new or edit existing calendar
Go to the "Conditional Colors" tab
Choose the necessary condition and color in which to paint your tasks.
Click edit or create.
The created colors will be visible to everyone who uses the calendar. If you need your own colors, use the user conditional colors.