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