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