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