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