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