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