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