To change Day View display options, follow the below instructions:

Login to Calendar -> Go to Admin Menu -> Options -> Expert Options Tab -> Under "Day View Controls" check the appropriate settings ->  [Save] Changes

day view options
If you prefer to control the Day View Display Options via a url parameter, you can do so by inserting the following arguments into calendar url rather than setting in directly in the calendar.

&showcatday=1 (shows categories in day view)
&nobarsday=1 (removes bar graph from day view)
&showdescday=1 (shows event descriptions in day view)
&desclenday=200 (tuncates the event description at specified number of characters)

Here is an example of a link with all these arguments turned "on." Be sure to replace your unique calendar identifier where is says "calendaridentifier."

http://www.calendarwiz.com/calendars/day.php?crd=calendaridentifier&showcatday=1&nobarsday=1&showdescday=1

Replace the "1" in the link with a "0" to see turn the argument "off" in the url.