Hmm, it should be on the left there follow those 2 ribs down into the dark shadowed area, I take it you have cleared and cleaned the area with some air to see if its hiding under oily saw dust and dirt ?
If not, its time to remove the clutch and cover that goes around the clutch drum and have a closer look under there.
Pretty Odd that its got an oil pump on that saw with no adjuster, didnt realise there was a pump without adjustment that would fit that saw.
Post some more pics, here is an IPL to help you along too.