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