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