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