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