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