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