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