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