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