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