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