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