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