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