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