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