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