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