In Microsoft Office 365, color information is not stored directly in a calendar. Category name information, however, is stored. If you want to make sure that other people see colors the same as you do on your calendar, you must use a standard set of categories for your team.
The easiest approach is to use the existing standard categories for Outlook, which are:
If you want others to see the same colors that you see for an event, you must not rename these categories. (If you did change them, you can change the names back to these standard names if you wish).
If you want to use other categories, your entire team must also use the same category name that you do. They can create categories for their own calendar view and assign it an agreed upon color.
To create a custom category from Outlook
When you share the calendar with someone else, the other person will not initially see the colors for custom categories you have designated in the shared calendar. To see them they must:
Also, PLEASE do not seek out a different calendar system to use, That just creates IT confusion and gives us yet another system we get to maintain! Thanks for your cooperation. :)