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