I live down the road from Ngong Ping. If your flight was later, by far your best bet would be to ride the cable car (w-w-w.np360.com.hk/en/buy-book/pricing-and-packages/) down to Tung Chung! Its a great journey! $210 return or $145 one way. Trouble is it doesn't start until 10am on a weekday.
Your best bet is to take the bus from Ngong Ping to Tung Chung then catch an airport bus for about $4 or a taxi for around $40. The first bus from Ngong Ping to Tung Chung on a Monday morning leaves at 08:10 - see timetable here (nlb.com.hk/route/routemap/22). Journey time is around 45 minutes and costs $17.
Alternatively call +852 2984 1328 for a blue Lantau taxi. Cost about $200 but expect to be told 'No taxi please try again' as they hang up.
Good luck and enjoy, its a nice place up there and will be even nicer in the evening early morning without the hoards...
PS - I just registered so I cannot post URLS...