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