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