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