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