No, it doesn't necessarily... When people are faced with language related questions, their eyes often dart to the right, and when faced with spacial questions a persons eyes are more likely to dart to the left. This is hypothesized to be a consequence of our brain's specialized functions (as the right and the left side of the brain are used for different things) but the relation between the two isn't proven.
So looking to the left doesn't mean it's a lie. Unless, however, looking to the left is a person's tell. Like in poker, how people might touch their ear when lying, looking to the left can be a similar thing. However so can looking to the right. Or up or down.
So if you see a person look to their left, it doesn't mean they're lying at all. Unless you've noticed that they do it every time they've lied in the past, in which case yes, they're probably lying.
(edit: me and MrNu replied at the same time. His answer is similar, but with a lot more uncertainty and "window to the soul" bullshit. So if you want a shorter, more accurate reply, here ya go.)