If you want to manage your own history of data, then yes you will need to build the data into an array and wire that to a graph. Don't forget to remove the old data from the array as time progresses.
Is the Arduino collecting the data at any specific rate? Is it sending the data at the same rate to LabVIEW? Is the rate as high as what the o-scope is set for? My guess is that the answer to one or more of these questions is no and that is why your view doesn't match the o-scope.
