They don't call it a "citation graph" but for each publication you pull up, if they have the data, all the citations are hyperlinks to the pages for those cited

They don't call it a "citation graph" but for each publication you pull up, if they have the data, all the citations are hyperlinks to the pages for those cited publications. So from each document, you can walk backwards to those that it cites. In the past they also had a "cited-by" link-set on each document, which provided the ability to walk forward to documents which cite the one shown. But looking at their cite now (it has been a while since I looked at them) the forward citation links appear to be missing, which looses half the citation graph.