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