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