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