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