To search for accommodation in a university college, you can visit this link
Each college has its own website but booking a room is available via this website. The colleges closer to the event venue, and all between 15 and 20 minutes walk, are:
The University of Cambridge has also this website, which reports lots of accommodation options of various price ranges.
When booking accommodation, take into account that the event will begin on Monday around 09:00 and will end on Friday around 19:00.