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