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