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