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