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