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