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