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