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)(11,17)(12,13)(14,15)(16,18)(19,20)(21,23)(22,24)(25,26,30,31)(27,35,36,32)(28,33,38,40)(29,37,39,34)(2,5)(6,7)(10,15)(11,18)(12,21)(20,24)(26,31)(27,36)(33,40)(34,37) involution — undirected(1,2)(3,6)(4,5)(7,8)(11,18)(12,21)(13,23)(16,17)(26,31)(27,36)(28,38)(29,39) involution — undirected(1,3)(2,6)(4,8)(5,7)(9,11)(10,16)(12,22)(13,20)(14,18)(15,17)(19,21)(23,24)(25,27,30,36)(26,32,31,35)(28,34,38,37)(29,33,39,40)(9,12)(10,13)(11,19)(14,21)(15,23)(16,24)(17,20)(18,22)(25,28,30,38)(26,33,31,40)(27,37,36,34)(29,35,39,32)(9,13)(10,12)(11,20)(14,23)(15,21)(16,22)(17,19)(18,24)(25,29)(26,34)(27,33)(28,35)(30,39)(31,37)(32,38)(36,40) 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.