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