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