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