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