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