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