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