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