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