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