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