There are plans and photos in the book "The Newton Abbot to Kingswear Railway(1844 - 1988)" by CR Potts, published by Oakwood Press. Looking at the fold-out plan at the back of the book, the plan may be of the track layout from a slightly earlier period, as it shows an outward extension of the jetty in 1921 (and also my grandfather in his younger days!!) However, from my recollection, the layout changed little, if at all during my childhood and youth days days there, early 40's - early 60's.
Perhaps you could order the book from your local library. Best wishes. Roger Farleigh