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