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