think of each sub in the picture as a pair, thats 2 subs... wire each pair of subs together from the positive on one sub to the negative on the other, so on and so forth its a little bit of work, but what did you expect with 6 subs...
also asking someone to post a diagram isnt needed, you have a perfectly good example, which if you cant understand you shoulld probably not be messing with it... i suggest you try to do a little bit of research i know you may not have alot of time, but read up educate yourself so that you dont have to learn the expensive way, your current setup with your subs wired te way they are could kill your amp or damage your speakers