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