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