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