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