This is a two step process. First step is to get the user list and current status. this is pretty easy, you will want to use object "presence" and action "list". This can be done form nearly any scope. You will also need to add in the domain filter, but that should be the only filter needed. This will return a small field set for all the users in the domain including first, lastname, username, current status message, and current presence value matching the presence value shown in the admin portal (open, closed, inuse, busy, etc..). You will need to match the values and draw your panel from there.
As for live data you will need to "subscribe" to the api using the "events" object and action "create". You will need to give the following settings, domain, model ("presense"), post_url which will be a full url where the API will post changes to your app and an optional "expires" field (default is expires time of the token used).
From there the API in partnership with a node.js server will stream changes to the url given. The results will be in JSON.
Chris