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