configuration mode on canvas

I am creating a switch visualisation system for IT managers, one of the features I am adding is creating a new authorization relationship between one switch to another. so that one switch is the server (gives approvals) and all of the other switch are his clients. and now for the question: I need to create a mode where the user can configure the client - server relationships. I thought about changing the interface colors, like in adrenaline mode in shooter games (Call of duty for example), do you guys have any suggestions how can I show the user that he is in a configuration mode? be creative :)+