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