Obligatory joke about drinking and how this level had me drowning myself in alcohol.

• Brute force
  
• Pretty coloured lights

The brute force method will require you to click every rock to achieve the 625 different colour combination, whilst attempting to open each clam on each pass.

Whilst this works, it is not particularly efficient.

There was another level where we had some colours
Maybe you should bunker down for the night and think about it.

There might be a switch of some sort that will start a sequence of flashing lights

Well, that's entirely up to you, I'm not going to judge

Starting from the left the combinations are:
red green green yellow
pink blue pink red
blue yellow red pink

make sure you click the pearl as well.