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)(13,14,20,17)(15,23,27,28)(16,19,22,18)(21,26,24,25)(2,4)(13,15,20,27)(14,21,17,24)(16,23,22,28)(18,26,19,25)(6,9)(10,12)(13,16)(14,19)(15,24)(17,18)(20,22)(21,27)(23,25)(26,28) involution — undirected(13,17,20,14)(15,23,27,28)(16,18,22,19)(21,26,24,25)(5,7,8,11)(6,10,9,12)(13,18,20,19)(14,16,17,22)(15,25,27,26)(21,28,24,23)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.