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