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