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