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