We are flying in to Guangzhou Airport at 5am and out to Melbourne 14 hours later.

You are eligible to the 24h visa-free policy. Just apply for a stay permit upon arrival, and you can check into a hotel outside.
For accommodation, you may consider the Hotel Landmark Canton which located at No. 8, Qiaoguang Road, Yuexiu District. It is adjacent to some interesting places, such as Haizhu Square, Beijing Road Pedestrian Street, and Pearl River. You can go shopping, taste local snacks and have a cruise on Pearl River.

From the airport, you can take metro line 3 to Jiahewanggang Station, and change to line 2 to Haizhu Square Station, Exit F. Walk east for about 100 yards and walk south for about 100 yards. After that, you can easily find the hotel. Hope you like. :)

Dear Julie, you can also stay near the airport. The Pullman Hotel to the opposite of Gate 13, Departure Hall is highly recommended. The hotel provides comfortable environment and quality service. You will have a good rest there. You can contact the hotel through infopullmanguangzhou.com.