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