Weird graph from the Riemann zeta function – mathoverflow.net

In this video: https://youtu.be/JUrACHCmJXs?si=7z7Dw80M4jS4Jg8S at 2:15 he shows the graph of the difference between $\pi(x)$ and $\mathrm{li}(x)$. When I tried to graph it its nothing alike. How did ...