Switch with 2 red, 2 black and 1 ground wire
Connect the line to the one hot wire.  The black wire in its cable gets capped off. Connect the load to the black or red wire of the other cable, you'll know you have the right one because the light will work.  Cap off the other one.  

This combination will work until you find one of the other 3-way or 4-way switches in the system.  Then, it will fail until you throw that switch back.  Your layout is 

  ---- 3way ==== 4way ==== 3way ----
  ----------------------------------


or 

  ---- 3way ==== 4way ==== 4way ==== 4way ==== 3way -----
  -------------------------------------------------------


with any number of 4ways in the middle.  

I have a personal rule that "the last guy" probably had a pretty good reason for doing it that way.  So before you take a wrecking ball to his work, look for those reasons.  Otherwise later, you'll be going "Gosh, it'd be a lot more convenient if it worked like --- oh right, it already did and I destroyed it  because I didn't understand it".  Those 4-way switches are about $10 each, people don't use those without a pretty good reason.