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