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