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