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