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