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