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