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