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