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