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