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