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