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