a) What does the Torah say about one's face?
b) What the does one's face represent?
c) Does one's face have a connection to his soul?
The Gemara (Brachos 58a) writes that just as the appearance of one's face is unique, so is one's personality. R. Tzadok of Lublin (Dover Tzedek) explains this comparison on the principle that
עיקר הנפש היא בפנים
Rough translation: The soul is mostly in the face.
R. Ezekiel Landau explains the Gemara similarly (Tzlach to Berachos ch. 9 58b I think)
This explanation is probably rooted in the kabbalistic belief of חכמת הפרצוף equivalent as far as I can tell to Physiognomy. See also reference to it here. For an example of this belief in rabbinic literature see R. Bachye's commentary to Yisro (ch. 18).