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