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