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