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