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