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