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