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