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