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