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