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