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