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