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