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