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)(11,13,18,16)(12,20,21,17)(19,24,22,23)(25,26)(27,29)(28,36)(30,31)(32,35)(33,39)(34,40)(37,38)(2,6)(3,7)(10,15)(12,21)(13,16)(19,22)(26,31)(29,32)(33,36)(38,40) involution — undirected(1,3)(2,4)(5,7)(6,8)(10,15)(11,18)(17,20)(19,22)(25,27,30,35)(26,29,31,32)(28,34,39,37)(33,38,36,40)(1,4)(2,3)(5,8)(6,7)(9,11)(10,16)(12,22)(13,15)(14,18)(17,23)(19,21)(20,24)(25,27)(26,32)(28,37)(29,31)(30,35)(33,38)(34,39)(36,40) involution — undirected(9,12,14,21)(10,17,15,20)(11,19,18,22)(13,23,16,24)(25,28,30,39)(26,33,31,36)(27,34,35,37)(29,38,32,40)(9,13,14,16)(10,11,15,18)(12,23,21,24)(17,19,20,22)(25,29,30,32)(26,27,31,35)(28,38,39,40)(33,34,36,37)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.