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