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