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