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