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