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)(25,26,30,31)(27,35,36,38)(28,37,39,32)(29,33,40,34)(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)(27,36)(32,37)(33,34)(2,5)(6,8)(9,12,14,13)(10,16,18,17)(11,20,22,21)(15,23,19,24)(25,27,29,32,30,36,40,37)(26,28,34,35,31,39,33,38)(1,3,4,7)(2,6,5,8)(9,12,14,13)(10,17,18,16)(11,21,22,20)(15,23,19,24)(25,28,30,39)(26,32,31,37)(27,34,36,33)(29,35,40,38)(9,13,14,12)(10,16,18,17)(11,21,22,20)(15,23,19,24)(25,29,30,40)(26,33,31,34)(27,32,36,37)(28,38,39,35)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.