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