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