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