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