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