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