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