At first glance there is not much in this poem to remind us of Latin, except perhaps for the “murmuring labours” of the Etonians studying their vocab or irregular verbs. However, it is pure “carpe diem”, and the personified human misfortunes it lists are a pretty close borrowing from Book 6 of the Aeneid. See the Aeneid text, and the whole of the Gray poem, here.
The picture is one of a sequence illustrating the poem by William Blake.