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)(11,23)(12,28)(13,32)(14,22)(15,20)(16,21)(17,25)(18,30)(19,24)(26,36)(27,35)(29,38)(31,39)(33,40)(34,37) involution — undirected(2,5)(6,8)(9,11,15,27,16,26,14,25)(10,17,22,36,21,35,20,23)(12,24,31,34,30,33,29,13)(18,37,39,19,28,32,38,40)(9,12)(10,18,21,28)(11,24)(13,25)(14,29)(15,31)(16,30)(17,32,35,37)(19,36,40,23)(20,38,22,39)(26,33)(27,34)(1,3,4,7)(2,6,5,8)(9,13,14,33,16,34,15,24)(10,19,20,37,21,40,22,32)(11,12,25,29,26,30,27,31)(17,28,23,39,35,18,36,38)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.