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