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