The nearest attraction to the airport is big Buddha statue at at Po Lin Monastery. But according to your timing, the time is not enough. I would probably suggest you to stay in the lounge. In the morning there is a risk to stuck in a traffic jam too, and it would be rather a stressful experience for a layover. There are quite plenty of things to do at the airport, like an IMAX movie at UA Cinemas or the golf simulator GreenLiveAIR which is located in Terminal 2 at Departures Level 2.