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)(25,26)(27,34)(28,32)(29,38)(30,33)(31,37)(35,39)(36,40)(2,5)(6,8)(9,11)(10,14)(12,18)(13,17)(15,22)(16,21)(19,24)(20,23)(25,26)(27,31)(28,38)(29,32)(30,33)(34,37)(35,40)(36,39) involution — undirected(11,17)(14,21)(18,23)(22,24)(25,27,29,37,30,36,28,35)(26,31,32,34,33,39,38,40)(9,12,13,20)(10,15,16,19)(11,18,17,23)(14,22,21,24)(25,28,30,29)(26,32,33,38)(27,35,36,37)(31,34,39,40)(1,3,4,7)(2,6,5,8)(27,36)(31,39)(34,40)(35,37)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.