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