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