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