I would use color-coding. Well, as long as the program allowed me to set the colors for each item (as per your suggestion). Otherwise, using someone else's forced color-coding be terrible.
FYI: when renaming objects, I often start the names of similar objects with something that indicates what it is. For example, names for buttons (even when they're technically shapes with triggers) start with "b," such as "b-step1," "b-step2," etc. That makes them easy to spot in the timeline, and it groups them in alphabetical lists, such as when selecting items in the Trigger Wizard. (Good naming conventions also make it easier to troubleshoot.)