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