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