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