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