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