One vertex per element, one color per generator, with an edge from x to x·s.
(2,4)(5,6)(7,11)(8,10)(9,12)(14,18)(19,27)(20,21)(22,28) involution — undirected(5,7,9,8)(6,10,12,11)(13,14)(15,22)(16,18)(17,20)(19,24)(21,25)(23,28)(26,27)(1,2,3,4)(5,7,9,8)(6,11,12,10)(13,15,16,23)(14,19,18,27)(17,26,25,24)(20,22,21,28)(5,8,9,7)(6,10,12,11)(14,20)(17,25)(18,21)(19,22)(24,26)(27,28)(15,23)(19,27)(22,28)(24,26) involution — undirectedA 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.