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