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