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