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