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)(27,34,33,30)(28,36,37,32)(35,38,39,40)(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)(27,33)(32,36)(35,39)(2,5)(6,8)(9,12,14,13)(10,16,18,17)(11,20,22,21)(15,23,19,24)(25,27,30,26,29,33,34,31)(28,35,38,32,37,39,40,36)(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)(27,35,33,39)(30,38,34,40)(9,13,14,12)(10,16,18,17)(11,21,22,20)(15,23,19,24)(28,37)(32,36)(35,39)(38,40)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.