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