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