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