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