Here is the official website of Puerto Cayo it has a few listings of hotels, and a list of activities available in the area, but currently (12/2015) no live links for whale watching tours, etc. You can arrange whale watching tours here. Whale watching tours can also be arranged from Puerto Lopez.
A useful blog about life in Puerto Cayo
Retiring in Ecuador BlogSpot is a blog written by a Canadian Expat who lives in Puerto Cayo. He has information about life in Puerto Cayo as well as other information about living in Ecuador that is useful. Here is a video that he produced himself.