You just have to enable it first.

    $ cupsctl WebInterface=yes

Yeah, it's great for setting stuff like printing defaults so you don't have to set the print quality or page size over and over again (unless I'm missing an obvious way to do it in System Preferences?).

I have my printer added multiple times with different default configurations; eg b&w-draft-printer, colour-photo-printer; it's much easier than messing with settings all the time.

Also it's the only way to disable a printer from certain users. (Great when a 5 year old is kept quiet on a laptop to discover she can print from Chrome's PDF viewer and starts manically laughing at sending 20 colouring in sheets to the printer...)

No, there's no other obvious way. You can create and edit presets in print dialogs (unless you're using an app that refuses to use system print dialogs like Chrome), and the printer can default to the last used preset, so that covers the most common use cases.

Happy to know about the web interface though, that will be very handy!

Not obvious, but you can also use the command line tool lpadmin.

I can’t remember if it’s enabled by default but it’s at localhost:631