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