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