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