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)(25,26,29,34,30,32,28,39)(27,35,38,40,37,33,36,31)(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)(26,31)(28,38)(29,36)(30,37)(32,40)(33,34)(35,39)(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)(26,32)(27,36)(29,30)(33,35)(37,38)(1,4,5,3)(2,6,8,7)(12,20)(16,21)(18,24)(22,23)(25,27)(26,33)(28,36)(29,38)(30,37)(31,34)(32,35)(39,40)(9,12,13,20)(10,16,14,21)(11,18,19,24)(15,22,17,23)(27,37)(31,40)(33,35)(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.