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