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