Although specs put out by Ducati will disagree, the S has Marchesini wheels (non S has Enkei) and outside air temperature gauge (non S does not). Actually, this may only be the case on US bikes. Some of us US owners discovered that our non S's have Enkei wheels and no air temp gauge. The other market non S might have those items.
Other than that, yeah it's the Ohlins suspension and various carbon fiber bits, including the front (and rear?) fenders.
Don't forget that the front disc carriers on the S are aluminum vs. steel on the non S. I think I read somewhere that this results in about a one and a half pound loss of reciprocating and unsprung weight of which both are a significant advantage. Of little benefit is also the carbon fibre heat shields.