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