1. A system to allow an analyst to analyze event streams of a user session and graphically display a result, the system comprising: at least one hardware-based processor having memory coupled thereto; a log file configured to interface to one or more log sessions from a user-generated event stream, the event stream being generated by various on-line states from the user session in a communication network; a query composer comprising a query language and a front-end filter coupled to the log file, the query composer configured to provide one or more conditions to sort the event stream; a graph visualizer coupled to the query composer and configured to produce a probability distribution of event nodes from a given node in the event stream, the graph visualizer being further configured to produce a graphical reduction of a produced graph by determining patterns in a graphical tree and unifying occurrences of the patterns, the graph visualizer further to compute a similarity threshold level to produce the graphical reduction, make a determination whether two or more sub-trees in different paths of the graphical tree each have a similarity threshold value greater than the similarity threshold level, and merge the two or more sub-trees having the similarity threshold value greater than the similarity threshold level into a single sub-tree; and a graph generator coupled to the query composer configured to apply the one or more conditions to the event stream and generate a graph file, the graph generator being further configured to generate at least two types of results from each query request provided including a first plurality of pages visited in the user session and a last plurality of pages visited in the user session.