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