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