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