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