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