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