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