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