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