Layover tour in Guangzhou hiring a taxi for 4 to 5 hours and back to airport to catch up flight?

Hi, I am arriving CAN Baiyun Airport from Beijing at 17:00 on 30 March. I have next flight at 03:00 on 31st March. We are 04 and will have 4 to 6 pc luggage. Can I take a tours by Taxi from airport to see places of attractions, and do little shopping in street markets for 4 to 5 hours and back to airport to catch the flight!! What may be the cost? Is there scope to leave the luggage in the airport in any store!! Please help.