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