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