Color Code your Sharepoint 2013 Calendar Items based on Category or any column values
I referred to following blog which is for sharepoint 2010
https://davidlozzi.com/2012/01/26/color-code-your-sharepoint-calendar/
its great help and it just works the same way in sharepoint 2013 on the cloud or on premises .
Amazing feature of calendar overlays .
Thanks to David Lozzi