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