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