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