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