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)(11,17)(12,13)(14,15)(16,18)(19,20)(21,23)(22,24)(25,26,30,34)(27,35,36,31)(28,32,38,39)(29,33,37,40)(2,5)(6,7)(10,15)(11,18)(12,21)(20,24)(27,36)(28,38)(31,35)(32,39) involution — undirected(1,2)(3,6)(4,5)(7,8)(11,18)(12,21)(13,23)(16,17)(25,27,30,36)(26,31,34,35)(28,29,38,37)(32,40,39,33)(1,3)(2,6)(4,8)(5,7)(9,11)(10,16)(12,22)(13,20)(14,18)(15,17)(19,21)(23,24)(25,28,30,38)(26,32,34,39)(27,37,36,29)(31,33,35,40)(9,12)(10,13)(11,19)(14,21)(15,23)(16,24)(17,20)(18,22)(25,29,30,37)(26,33,34,40)(27,28,36,38)(31,39,35,32)(9,13)(10,12)(11,20)(14,23)(15,21)(16,22)(17,19)(18,24)(25,26)(27,35)(28,32)(29,33)(30,34)(31,36)(37,40)(38,39) 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.