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