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