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