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