This is from a sutra where Shakyamuni Buddha tells people to recite the names of these eight Sugata's, the names of the eight Bodhisattvas and remember the eight gods mentioned in order to eliminate problems. So there could well be a thangka or a depiction of some sort.
All the teaching I have heard on this prayer has been oral. But I'm pretty sure that Lama Zopa has teaching published (mainly because he taught on it orally and probably Lama Yeshe as well).
Kirt's Tibetan Translation Notes
"Even if you practice only for an hour a day with faith and inspiration, good qualities will steadily increase. Regular practice makes it easy to transform your mind. From seeing only relative truth, you will eventually reach a profound certainty in the meaning of absolute truth."
Kyabje Dilgo Khyentse Rinpoche.
"Only you can make your mind beautiful."
HH Chetsang Rinpoche