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