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