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