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