Files in /usr/sbin are executable files rather than scripts so you're likely to get what looks like rubbish, they're binary, the clue's in the directory name.
Try
Code:
$cat | more /usr/sbin/visudo
which will also be unintelligible, mainly unprintable characters.
For information, visudo is the command used to edit the sudoer's file, why do you want to edit it, the command that is?
Play Bonny!