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