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