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