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