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