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