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