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)(11,19,21,15)(12,16,13,18)(20,24,22,23)(25,26,30,31)(27,32,36,40)(28,37,35,33)(29,34,39,38)(9,11,14,21)(10,15,17,19)(12,20,13,22)(16,23,18,24)(25,27,30,36)(26,32,31,40)(28,34,35,38)(29,37,39,33)(2,6)(7,8)(9,12,14,13)(10,16,17,18)(11,20,21,22)(15,23,19,24)(25,28,30,35)(26,33,31,37)(27,29,36,39)(32,38,40,34)(1,3,5,4)(2,7,6,8)(10,17)(15,19)(16,18)(23,24)(25,26,30,31)(27,32,36,40)(28,33,35,37)(29,38,39,34)(1,4,5,3)(2,8,6,7)(9,13,14,12)(10,18,17,16)(11,20,21,22)(15,23,19,24)(25,29,30,39)(26,34,31,38)(27,35,36,28)(32,33,40,37)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.