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