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