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