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