That is why I love hockey, they already give you a penalty for taking a dive, which has be renamed to "embellishment". It is a minor penalty (equivalent to a foul in the NBA). So start giving personal fouls, soon as Harden has 3 or 4 fouls by half he will stop.
If the ref can't tell, but a players over sells it, call offsetting fouls. Again, hockey will do this if there is a penalty, but the player "embellishes" the call they, will call one on him too. A ref should be able to tell if a player is over selling it (aka a player flying back like they got shot, when everyone knows a guy that large shouldn't move that far unless is it Shaq hitting them).