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)(11,19)(12,21)(13,17)(14,20)(15,18)(16,22)(23,24)(25,26)(27,30)(28,31)(29,33)(32,37)(34,38)(35,40)(36,39) involution — undirected(1,3,5,4)(2,6,7,8)(9,11)(10,12)(13,21)(14,16)(15,24)(17,19)(18,22)(20,23)(25,27,29,35)(26,30,33,40)(28,36,37,34)(31,39,32,38)(1,4,5,3)(2,6,7,8)(9,12,13,19)(10,16,17,24)(11,20,21,18)(14,23,15,22)(26,31)(28,37)(30,38)(32,33)(34,36)(39,40)(2,7)(6,8)(10,17)(12,19)(18,20)(22,23) 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.