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