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