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