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