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)(15,19)(16,21)(17,20)(18,22)(23,28)(24,26)(25,27) involution — undirected(5,7,9,8)(6,10,11,12)(13,15)(14,19)(16,24)(17,25)(18,23)(20,27)(21,26)(22,28)(1,2,3,4)(14,20)(15,23)(16,25)(18,24)(19,21)(27,28)(5,8,9,7)(6,10,11,12)(13,16,17,23)(14,21,20,28)(15,24,25,18)(19,26,27,22)(15,16)(18,24)(19,21)(22,26)(23,25)(27,28) 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.