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