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