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