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