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