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