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