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