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