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