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