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