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