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