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