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