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)(11,17)(12,14)(13,21)(15,20)(16,19)(18,23)(22,24)(25,26,30,29)(27,31,34,37)(28,32,36,38)(33,39,40,35)(1,3,4,8)(2,5,6,7)(10,14)(11,18)(13,19)(15,22)(25,27)(26,31)(28,35)(29,37)(30,34)(32,33)(36,39)(38,40)(9,11,19,24,12,18,13,20)(10,15,21,23,14,22,16,17)(25,28,30,36)(26,32,29,38)(27,33,34,40)(31,39,37,35)(2,6)(5,7)(10,14)(15,22)(16,21)(17,23)(25,26,30,29)(27,31,34,37)(28,32,36,38)(33,39,40,35)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.