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