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