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