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)(27,34)(29,37)(36,39) 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)(25,26,30,31)(27,28,34,32)(29,33,37,38)(35,36,40,39)(1,3)(2,6)(4,7)(5,8)(10,16)(11,12)(18,22)(19,20)(25,27,30,34)(26,32,31,28)(29,35,37,40)(33,39,38,36)(9,12,15,11)(10,17,16,13)(14,20,24,19)(18,23,22,21)(25,27)(26,28)(29,35)(30,34)(31,32)(33,36)(37,40)(38,39)(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)(26,27)(29,36)(30,32)(31,34)(33,35)(37,39)(38,40)(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)(26,33)(27,35)(28,36)(30,37)(31,38)(32,39)(34,40)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.