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