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