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