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