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