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