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