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