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