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