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