Do you mean changing the default color for appointments assigned to a particular Sage CRM user in the Team CRM calendar?

It did not say the Sage CRM version above but here is the help article for Sage CRM 2024 R2 for "Changing appointment color for a user":

https://help.sagecrm.com/on_premise/en/2024R2/Administration/Content/Administrator/CS_Calendar-UserColors.htm#:~:text=You%20can%20change%20the%20default,x86)%25%5CSage%5CCRM%5CCRM

The steps are: 

1. Create a JavaScript file named responsiveTeamCalendarUserColors.js.
2. Add the following code to the file:
   Copy

   SageCRM = SageCRM || {};
   SageCRM.CUSTOM_TEAM_CALENDAR_USER_COLORS = {
   
   // Map user IDs to colors.
   "<user ID>" : "<color>",
   };

   Where

   <user ID> is the Sage CRM user ID.

   <color> is the color in which you want the appointments to be displayed.
   Use hex color code, for example #00DC00.

   You can add as many "<user ID>" : "<color>" pairs as you like. Use a comma as a separator.

3. Save and copy the file to the following folder on the Sage CRM server:
   <Sage CRM installation folder>\WWWRoot\js\custom

   By default, Sage CRM is installed to:
   %ProgramFiles(x86)%\Sage\CRM\CRM

4. Reset IIS on the Sage CRM server.
   You can do so by running the iisreset command at a command prompt.