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