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