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