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