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