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