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