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