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