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