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