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