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