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