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)(11,15)(12,14)(13,16)(17,20)(18,21)(19,22)(23,24)(25,26,31,34)(27,35,39,37)(28,29,30,33)(32,38,40,36)(1,3,4,7)(2,5,6,8)(10,14)(11,18)(16,17)(19,24)(25,27,30,38,31,39,28,36)(26,32,29,37,34,40,33,35)(2,6)(5,8)(9,11,12,18)(10,15,14,21)(13,19,20,24)(16,22,17,23)(25,28,31,30)(26,29,34,33)(27,36,39,38)(32,37,40,35)(10,16)(13,20)(14,17)(15,22)(19,24)(21,23)(25,29,30,34,31,33,28,26)(27,37,38,40,39,35,36,32)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.