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