There are a couple of ways to color code the view add page. The most robust option is the custom color coding rules option.
Go to Settings > Configuration > Scheduling
Make sure that color scheme for view/add is set to custom and save your changes.
After you have saved your changes, on the same page, at the bottom you can create new job color rules, or edit old ones.
You can set rules based on Job type, service type, or agreement.
Colors are not updated in real time. The color rules are reapplied to jobs every 15 minutes.