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