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