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)(11,15)(12,20)(13,21)(14,16)(17,18)(19,24)(22,23)(25,26)(27,34)(28,38)(29,33)(30,32)(31,37)(35,40)(36,39)(1,3,5,4)(2,6,8,7)(9,11,14,19)(10,15,16,24)(12,17,21,23)(13,22,20,18)(25,27,29,37)(26,31,33,34)(28,36,30,35)(32,39,38,40)(9,12,20,10,14,21,13,16)(11,17,22,24,19,23,18,15)(27,35)(28,30)(31,39)(32,38)(34,40)(36,37)(1,4,5,3)(2,7,8,6)(25,28,29,30)(26,32,33,38)(27,36,37,35)(31,39,34,40)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.