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