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