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