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