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