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