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