No, this is not possible. You can switch in menu Window to the Vertical Layout to see more characters of a line. But for very long lines even this would not help. You always have to scroll horizontally, best with Window - Synchronized Horizontal Scroll enabled.
It would be good if there would be an option that UltraCompare also automatically scroll left/right in nearly identical 2 long single lines when pressing Next Difference or Previous Difference.
Or at least the command View - Center on Difference works additionally also horizontally for nearly identical single lines and not only vertically. I think, the main problem here is that an automatical horizontal scrolling is only possible if a SINGLE line in both files exist which has at least 1 difference. If a block difference exist, an automatic horizontal scrolling could be problematic.
However, write a feature request email to IDM support for an automatical horizontal centering of a difference in a sinle long line. I (Mofi) support this feature request.