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