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