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