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