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