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