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