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