By preserving angles obviously, har.. har...
In all seriousness, I can appreciate the Lorentz group for 4D being written $O(1,3)$ the same way we write our spacetime $\mathbb{R}^{1,3}$. The Lorentz group is turned inside out in all undergraduate curriculums.
I get that in $O(2,4)$ the extra "temporal" part arises from out dilations and special conformal transformations but it remains very abstract to me and I haven't been able to find any source that goes through the process so that it is no longer something I just accept that has been derived and move on. I came upon the topic when looking at the compactification of $\mathbb{R}^{1,1}$
Appreciate any help!