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