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