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