I'm not aware of any built-in mechanism of jumping to the location of an error in the error log.
However, the default behaviour of errorformat is to include all of the makeprg output, so context can be seen in the quickfix window itself.
The errorformat described in :help errorformat-LaTeX includes a number of patterns specifically intended to hide matching lines from the quickfix window (see :help efm-ignore):
\%-GSee\ the\ LaTeX%m,
\%-GType\ \ H\ <return>%m,
\%-G\ ...%.%#,
\%-G%.%#\ (C)\ %.%#,
\%-G(see\ the\ transcript%.%#),
\%-G\\s%#,
Removing these should result in the entire log being displayed.
If that doesn't work, you could also try adding a catch-all pattern to the very end of your errorformat:
set efm+=%+G%.%#
This will match ALL lines which have not already been matched by an earlier pattern in your errorformat. The disadvantage of doing this is that commands like :cnext and :cprevious will no longer skip over these lines, as they would do if you left them unmatched.
(It's more usual to use the negative analogue of this: %-G%.%# as a catch-all to remove all previously unmatched lines from the output.)