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