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)(13,14,19,28,18,23,17,22)(15,24,16,20,27,25,26,21)(6,10)(11,12)(13,15)(14,20)(16,17)(18,27)(19,26)(21,23)(22,25)(24,28) involution — undirected(1,2,3,4)(5,7,9,8)(6,11,10,12)(13,16,19,27,18,26,17,15)(14,21,28,24,23,20,22,25)(5,8,9,7)(6,12,10,11)(13,14,17,22,18,23,19,28)(15,25,26,20,27,24,16,21)(13,17,18,19)(14,22,23,28)(15,16,27,26)(20,25,21,24)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.