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