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