You've got the concept right: G-N connected together when on generator power, not connected together when on shore power. There are innumerable ways of implementing it.
It looks like you're planing a 50 amp power inlet connector, to which either an extension cord (shore power) or the generator would be plugged. The G-N bond is in the cord leading to the generator, so it would be disconnected in order for shore power to be attached. Looks fine to me.