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