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)(27,36,37,33)(28,40,34,29)(30,35,38,39)(1,2)(3,5)(4,6)(7,8)(9,11,15,17)(10,12,16,20)(13,18,22,23)(14,19,21,24)(26,32)(27,37)(28,34)(35,39)(1,2,4,6)(3,5,7,8)(10,16)(11,17)(13,22)(19,24)(25,27)(26,33)(28,38)(29,39)(30,34)(31,37)(32,36)(35,40)(3,7)(5,8)(9,12,15,20)(10,17,16,11)(13,19,22,24)(14,23,21,18)(25,28,31,34)(26,29,32,40)(27,38,37,30)(33,39,36,35)(1,2)(3,5)(4,6)(7,8)(9,13)(10,14)(11,18)(12,19)(15,22)(16,21)(17,23)(20,24)(25,29)(26,34)(27,39)(28,32)(30,33)(31,40)(35,37)(36,38) involution — undirected(1,3)(2,5)(4,7)(6,8)(9,14)(10,13)(11,19)(12,18)(15,21)(16,22)(17,24)(20,23)(25,30,31,38)(26,35,32,39)(27,34,37,28)(29,33,40,36)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.