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