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