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