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