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