One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,5,6)(3,7,4,8)(9,10,12,16)(11,19,22,15)(13,26,25,17)(14,18,20,30)(21,37,27,31)(23,32,40,38)(24,36,29,33)(28,34,39,35)(2,6)(7,8)(9,11,20,24,12,22,14,29)(10,15,30,33,16,19,18,36)(13,27,39,40,25,21,28,23)(17,31,34,38,26,37,35,32)(1,3,5,4)(2,7,6,8)(10,16)(11,21,22,27)(13,28)(14,20)(15,31,19,37)(17,34)(23,24,40,29)(25,39)(26,35)(32,36,38,33)(1,4,5,3)(2,7,6,8)(10,16)(15,19)(17,26)(18,30)(31,37)(32,38)(33,36)(34,35)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.