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