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