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