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