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