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