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