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