One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,6)(3,7,8,5)(9,10,13,16)(11,20,21,23)(12,22,17,24)(14,19,15,18)(27,33)(29,37)(31,39)(32,36)(34,40)(35,38)(1,3,4,8)(2,5,6,7)(10,16)(11,21)(18,19)(22,24)(25,26,30,28)(27,34,35,31)(29,32,37,36)(33,40,38,39)(9,11)(10,17)(12,16)(13,21)(14,24)(15,22)(18,23)(19,20)(25,27,30,35)(26,31,28,34)(29,38,37,33)(32,40,36,39)(9,12,13,17)(10,11,16,21)(14,23,15,20)(18,22,19,24)(25,28,30,26)(27,34,35,31)(29,32,37,36)(33,39,38,40)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.