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