One vertex per element, one color per generator, with an edge from x to x·s.
(2,3)(5,6,10,12)(7,8,11,9)(13,14)(15,22)(16,20)(17,19)(18,23)(21,25)(24,28)(26,27)(1,2,4,3)(5,7)(6,8)(9,12)(10,11)(13,15,16,23)(14,18,20,22)(17,26,25,24)(19,28,21,27)(6,11)(7,12)(8,9)(14,19)(17,25)(18,27)(20,21)(22,28)(24,26) involution — undirected(1,3,4,2)(5,8,10,9)(6,11,12,7)(14,20)(18,22)(19,21)(27,28)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.