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