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