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