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