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