Have you ever wanted to color your SharePoint calendars like you can in Outlook colors? Well, you can! It is a rather simple process that Joe Preiner at DEG Digital clearly lays out in his blog post "Four Easy Steps to Customized color Code Calendars in SharePoint."
Mr. Priener does a great job of giving users step-by-step instructions, so I'm simply going to refer you to his website as there is no need for me to further expand on the steps.
Cheers!