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