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