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