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