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