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